The present invention relates essentially to the use of laminarin and oligosaccharides derived from laminarin in cosmetology and for the manufacture of a medicine destined for the treatment of the skin.
It is known that laminarin is a storage polymer of brown algae and consists of polysaccharides whose structures differ slightly according to the nature of the alga.
In general terms, laminarin possesses a molecular mass of less than about 30000 Daltons and consists of 20 to 60 D-glucopyranoside units distributed in a main linear chain, in which these units are joined by .beta.(1-3) linkages, and branches joined to this main chain by .beta.(1-6) linkages.
Some of these chains have a reducing terminal unit consisting of a mannitol unit. The existence of mannose units within this structure is also noted.
Laminarin is generally extracted from brown macrophytt marine algae of the Pheophyceae type, and in particular the Fucales or the Laminariales.
Various extraction methods can be used to obtain the laminarin.
Reference may be made for example to the method described by Black et al., Appl. Chem., 1951, 1, pages 505 to 517.
More generally, laminarin can be obtained from brown algae by any extraction process which enables the constituents other than laminarin (wall polysaccharides, salts, etc.) to be successively removed.
In particular, these processes use steps involving grinding, precipitation in an acid or basic medium, ultrafiltration and dialysis.
Laminarin is also marketed, for example by Sigma Chimie SARL.
Various scientific publications describe the eliciting properties of laminarin, suggesting its use for enhancing plant defense reactions.
Thus Netzer et al. reveal that an infection with the pathogen S. oxysporum triggers the induction of laminarinase (Biological abstracts, vol. 68, No. 1, 1979).
Likewise, Bonhoff et al. reveal the properties of laminarin as an elicitor of phytoalexin and callose (Biological abstracts, vol. 86, No. 4, 1988).
Furthermore, Kurosaki et al. (Biological abstracts, vol. 35, No. 2, 1988) and Pearce (Biological abstracts Vol. 74, No. 8, 1982) confirm the eliciting effects of laminarin, in particular in respect of lignification, while at the same time state that these effects are weak compared with those of the known elicitors.
The French Patent Application No. 92 08387 of the Applicants confirm the eliciting properties of laminarin and its use for enhancing plant defense reactions, and further reveal that laminarin has the properties of an .alpha.-amylase elicitor causing an accelerating action on seed germination and plant growth.
Furthermore, it is known that sulfated laminarin has interesting pharmaceutical properties, in particular anti-coagulant and hypoi-holesterinemiant properties. (K. C. Guven et al., Introduction to Applied Physiology, 1990, pages 67 to 92).